But they hardly seemed to be able to make the case that it is unconsitutional. Most of it is full of question-begging about how "Senate rules can't conflict with the Constitution", which no one at all denies. What they'd need to demonstrate is that the rule does conflict with the Constitution. They could make their essay much shorter and to the point if they avoided trying to "prove" plainly obvious statements over and over again.
Actually I just now noticed this:
"Sherry Eros, MD, is a neuropsychiatrist and Steven Eros is a philosopher."
That explains it. Not much need to wade further.
I would argue that the Senate has an affirmative duty to accept or reject candidates put before it. If the Senate were to pass a rule at the start of its term mandating that all candidates would be rejected if they did not receive unanimous consent, I would argue that would be constitutional, but the purpose of a filibuster is not to accept or reject candidates, but rather to keep them from being acted upon one way or the other. And that, IMHO, constitutes deriliction of duty.
Filibustering of legislation generally does not pose the same problem, btw, because with very few exceptions there's no constitutional imperative to pass or even consider legislation. To be sure, I don't think congresscritters would have much fun if they never considered any legislation beyond what was Constitutionally required, but postponing indefinitely the discussions of non-required legislation falls entirely within legislative prerogative.